XMI12 — Bug in pseudo-code for PackageDTD

The pseudo-code for PackageDTD on p. 7-95 is inconsistent with the
EBNF. The EBNF states the requirements for when to generate a
CompositionDTD for an Association as follows: "The composition element
is generated for each Reference in the Package which has an exposedEnd
whose aggregation is composite." This means that if the one of the
AssociationEnds of a Association has an composite aggregation and the
referencing Reference's exposedEnd points to that same AssociationEnd,
only then should the composition element (CompositionDTD) be created.

The pseudo-code makes a similar, but weaker requirement. It requires
only that an Association contains an AssociationEnd that has a composite
aggregation. In fact, this would create duplicate declarations of the
Reference XML element if the referencedEnd of a Reference has a
composite aggregation, which is clearly wrong.